If your code is in debug mode and the directory path is correct then there can be a chance that due to HTML caching it's not working. Your breakpoint will hit the first time after that will retrieve data from the cache.
Could you please check that HTML caching is enabled on your rendering either on Item or Page level?
Go to the respective rendering and in caching section uncheck the caching options:
Go to the page and in presentation details check the same options in control properties windows:
Please confirm if the breakpoints in the VS code are not hitting or if they are not loading at all.
If in case the breakpoints in the class files are not loading at all then possible reasons can be -
Code is NOT compiled in DEBUG mode. From the Build menu, select Configuration Manager, then select Debug mode.
DLL's is deployed to Sitecore's Webroot Bin directory however generated .PDB file of the project is not deployed to the bin. Hence, ensure the .Dll and .PDB both files are deployed to the correct Sitecore application's bin directory.
You may not be attaching to the correct IIS Worker Process instance (w3wp). Find the correct application instance and attach the visual studio debugger to the application instance that runs using the deployed DLL.
4 Remove .NET Temporary Files to clear IIS Cache. Go to the following directory and delete every folder in there. C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files.
Restart Visual Studio, Reset IIS Application pool.